A woman in her twenties was found stabbed to death in the District early yesterday morning, at the end of a burst of violence that began Monday afternoon and included four homicides and at least eight shootings, police said.

The unidentified woman, who became the city's 359th homicide victim this year, was found about 1 a.m. in an alley behind the 1300 block of Girard Street NW. There are no suspects in the case.

There have been no arrests in three of the other killings, and police said they do not know the motive in those cases.

But police said the motive was robbery in the shooting death of Anthony Lee Dent, 24. The killing, which was seen by several people, occurred in the 3100 block of 15th Place SE.

Dent, of the 1000 block of Sixth Street NE, ran across the street as the shots were fired, falling wounded in the yard of an apartment building on the block. He was taken to D.C. General Hospital and pronounced dead.

The incident occurred about 100 yards from a shooting less than two hours earlier. In that incident, which police said was unrelated, a man was shot several times, apparently after a dispute. He was taken to Washington Hospital Center, where he underwent surgery yesterday.

About 10 p.m. Monday, the fire department responding to a call at the 3500 block of Sixth Street SE found Tyrone Wells, 20, suffering from gunshot wounds. He was taken to D.C. General, where he was pronounced dead about 3 a.m. Tuesday. Police said Wells, of the 1100 block of Kennebec Street in Oxon Hill, had been shot earlier in a parking lot on the 3500 block of Wheeler Road SE.

About 4:30 p.m. Monday, police responding to a report of a shooting on the 200 block of 51st Street NE found Michael James Hall, 18, unconscious and lying in a hallway. He was pronounced dead by the Medical Examiner's Office at 6 p.m.

Details were scant on the shootings that did not prove fatal, and police did not release the victims' names. Two of those victims Monday night were taken to Washington Hospital Center, which at one point decided to reroute additional patients as a precaution.

The shooting victims had to be treated at a time when other emergency surgeries were being performed, said Sandra R. Gregg, a hospital spokeswoman. The emergency room had reached capacity.